On systems in the engine or transmission compartment that come into direct contact with oil, seal systems for filling or draining the oil are required now and then. For the design of such seal systems a construction is usually chosen based on a combination of metal and plastic. This involves the use of profile seals or O-ring seals that ensure sealing between themselves or with the component being sealed. Even on housing components made of plastic, the filling and draining screws and their threads of the prior art are made of metal. Oil pans with seal systems of the prior art, for example, are produced by coating threaded bushings made of metal, usually of steel or brass, in the thermoplastic injection mold or subsequently pressing them with heat or with the aid of ultrasound into a location pre-molded in the plastic housing.
Another process involves pressing threaded bushings with a collar into the plastic container. This means that the embedded metal bushing has to satisfy exacting requirements in terms of retaining strength and positional accuracy. When threaded bushes are coated and the tolerances on the bushing or in the injection mold or the injection molding parameters are changed, there is a risk of the molten plastic penetrating at the ends of the bushing or even into the thread turns. On plastic moldings whose bushings are pressed in with heat or with the aid of ultra-sound there is the problem that molten plastic can also escape at the places mentioned above. Another problem concerns the recycling of such plastic moldings with embedded metal parts, since separating these different materials is a very complicated process.
The technical object was therefore to provide seal systems for sealing housing components made of plastic that avoid the above-mentioned problems and permit a reduction in cost, weight and process risks.